GLM-5.2 Open Weights: Route Reasoning Effort by Task

On June 17, 2026, Z.ai dropped the full MIT-licensed weights for GLM-5.2, and the dev timelines lit up. The reason is simple: it is a ~753B-parameter mixture-of-experts model that scores at the top of the open-source pack on long-horizon coding, lands second on Code Arena, and trails Claude Opus 4.8 by roughly a single point on independent multi-step coding evals. The kicker is price. VentureBeat reports it beats GPT-5.5 on long-horizon coding at about one-sixth of the cost, and the weights ship under MIT, so you can also self-host.